Parental age in Indian patients with sporadic hereditary retinoblastoma

Parental age and retinoblastoma-a retrospective study of demographic data and genetic analysis

OBJECTIVE

To determine the association between the parental age gap and the absolute parental age with the risk of retinoblastoma (RB) development in an offspring.

METHODS

RB individuals diagnosed between March 2013 and December 2019 in a single tertiary eye care centre were included. We recorded the demographic data, parental age and RB1 gene mutation status in the patient's tumour, blood and the parental blood. We categorised RB1 mutation inheritance as sporadic RB with somatic mutations (only present in tumour), heritable RB with de novo (present in patient's blood) and familial (present in patient and parents' blood) germline mutations. The statistical significance was confirmed by Fisher's exact/Chi-square test.

RESULTS

Out of 259 RB patients, 247 were included in our study. Heritable RB with de novo germline mutations was significantly less common (p value: 0.0387; 95% CI: 0.2676-0.9329) and sporadic RB with somatic mutations was more common (p value: 0.0545; 95% CI: 1.025-3.39), if the parental age gap was <10 years. There were increased odds of a heritable RB with de novo germline mutation with an increase in paternal age and this was more intensified when combined with parental age gap of more than ≥10 years. The heritable RB with de novo germline mutations significantly increased as maternal age progressed, only when it was adjusted to ≥10 years parental age gap (p value: 0.0262; 95% CI: 1.26-17.91).

CONCLUSIONS

An increased parental age gap and increased paternal age are independent risk factors for the development of heritable RB with de novo germline mutation.

Parental Occupation and Risk of Childhood Retinoblastoma in Denmark

OBJECTIVE

Retinoblastoma is the most common primary intraocular tumor affecting children. We examine the role of parental occupational exposures and risk of retinoblastoma among offspring.

METHODS

Our population-based case-control study linked data from four nationwide Danish registries and included all cases of retinoblastoma diagnosed in Danish children (<5 y, n = 144) between 1975 and 2014. We focused on two biologically relevant time periods: 90 days preconception to conception for fathers; conception to birth for mothers. Parents were grouped into major industry headings created from Danish industry codes.

RESULTS

We observed increased risk of all retinoblastoma for children of fathers in the food and drink industry and iron and metal industry. Bilateral disease was associated with paternal work in manufacturing and land transportation.

CONCLUSION

Our results suggest that some occupational exposures may increase the risk of childhood sporadic retinoblastoma.

Parental age and childhood cancer risk: A Danish population-based registry study

BACKGROUND

Though the association between parental age at child's birth and the risk of childhood cancer has been previously investigated, the evidence to date is inconclusive and scarce for rarer cancer types.

METHODS

Cancer cases (N=5,856) were selected from all children born from 1968 to 2014 and diagnosed from 1968 to 2015 in Denmark at less than 16 years of age listed in the nationwide Danish Cancer Registry. Cases were individually matched to controls (1:100) on sex and year of birth with a total of 585,594 controls randomly sampled from all live births in Denmark from the Danish Central Population Registry. Parental age at child's birth was extracted from the Central Population Registry. Conditional logistic regression models were used to estimate odds ratios for the association between parental age at child's birth and childhood cancer risk. Parental age was modeled as both categorical (referent group, parents aged 25-29) and continuous per 5-year increase in age.

RESULTS

Offspring of older mothers were at an increased risk of acute lymphoblastic leukemia [OR=1.10, 95% CI: (1.02, 1.19) per 5-year increase in age]. Older maternal age (40+) increased the risk of non-Hodgkin lymphoma [OR=1.96, 95%CI: (1.12, 3.43)]. The risk of Wilms' tumor also appeared elevated with older paternal age [OR=1.11, 95% CI: (0.97, 1.28) per 5-year increment in age].

CONCLUSION

Older parental age was a risk factor for various childhood cancers in Danish children. Further investigation of the biological and social factors that may be contributing to these associations is warranted.

Perinatal characteristics and retinoblastoma

PURPOSE

The etiology of retinoblastoma remains poorly understood. In the present study, we examined associations between perinatal factors and retinoblastoma risk in California children.

METHODS

We identified 609 retinoblastoma cases (420 unilateral, 187 bilateral, and 2 with laterality unknown) from California Cancer Registry records of diagnoses 1988-2007 among children < 6 years of age. We randomly selected 209,051 controls from California birth rolls. The source of most study data was birth certificates. Multivariable logistic regression was used to examine associations between retinoblastoma and perinatal characteristics.

RESULTS

Bilateral retinoblastoma was associated with greater paternal age [for fathers over 35, crude odds ratio (OR) = 1.73, 95 % confidence interval (CI) 1.20, 2.47] and with twin births (OR = 1.93, 95 % CI 0.99, 3.79). Among unilateral cases, we observed an increased risk among children of US-born Hispanic mothers (OR = 1.34, 95 % CI 1.01, 1.77) while a decreased risk was observed for infants born to mothers with less than 9 years of education (OR = 0.70, 95 % CI 0.49, 1.00), a group that consisted primarily of mothers born in Mexico. We observed that maternal infection in pregnancy with any STD (OR = 3.59, 95 % CI 1.58, 8.15) was associated with bilateral retinoblastoma.

CONCLUSIONS

This study supports the findings of previous investigations reporting associations between parental age, HPV infection, and retinoblastoma.

Evidence for the presence of high risk human papillomavirus in retinoblastoma tissue from nonfamilial retinoblastoma in developing countries

BACKGROUND

The prevalence of human papillomavirus (HPV) infection in India is high. HPV infection is known to cause cervical cancer and has also been implicated in the pathogenesis of retinoblastoma (RB), a common intraocular malignant tumor of childhood which can be familial or sporadic. Despite the high incidence of RB in India, its familial form is rare. Hence this study was undertaken to investigate whether high-risk HPV types 16 and 18 are involved in the development of RB.

METHODS

Formalin fixed paraffin embedded RB tissues (n = 76) including prospective cases with corresponding maternal cervical smears (n = 10) were analyzed for the presence of HPV DNA sequences. Expression of the cell cycle regulatory proteins viz; p105, p107, p30, p16, E2F-1, E2F-4, and MiB-1 was studied by immunohistochemistry (IHC) (n = 34).

RESULTS

A total of 53 out of 76 (69.7%) cases were positive for HPV, of these 3 cases were positive for HPV-16, 23 for HPV-18, and 27 for both HPV-16 and -18. Of the prospective cases (n = 10) studied, five cases along with the corresponding maternal cervical cytology smear had identical HPV status. HPV-16 positive tumors were classified as well differentiated (P = 0.013). Nuclear expression of pRB2/p130 showed significant association with HPV-16 infection (P = 0.04) or dual infection of HPV-16/-18 (P = 0.02).

CONCLUSIONS

Our study lends support to the hypothesis that infection of HPV-16/-18 may play an important role in the development of nonfamilial form of RB in children in India.

Mutation risk associated with paternal and maternal age in a cohort of retinoblastoma survivors

Autosomal dominant conditions are known to be associated with advanced paternal age, and it has been suggested that retinoblastoma (Rb) also exhibits a paternal age effect due to the paternal origin of most new germline RB1 mutations. To further our understanding of the association of parental age and risk of de novo germline RB1 mutations, we evaluated the effect of parental age in a cohort of Rb survivors in the United States. A cohort of 262 Rb patients was retrospectively identified at one institution, and telephone interviews were conducted with parents of 160 survivors (65.3%). We classified Rb survivors into three groups: those with unilateral Rb were classified as sporadic if they had no or unknown family history of Rb, those with bilateral Rb were classified as having a de novo germline mutation if they had no or unknown family history of Rb, and those with unilateral or bilateral Rb, who had a family history of Rb, were classified as familial. We built two sets of nested logistic regression models to detect an increased odds of the de novo germline mutation classification related to older parental age compared to sporadic and familial Rb classifications. The modeling strategy evaluated effects of continuous increasing maternal and paternal age and 5-year age increases adjusted for the age of the other parent. Mean maternal ages for survivors classified as having de novo germline mutations and sporadic Rb were similar (28.3 and 28.5, respectively) as were mean paternal ages (31.9 and 31.2, respectively), and all were significantly higher than the weighted general US population means. In contrast, maternal and paternal ages for familial Rb did not differ significantly from the weighted US general population means. Although we noted no significant differences between mean maternal and paternal ages between each of the three Rb classification groups, we found increased odds of a survivor being in the de novo germline mutation group for each 5-year increase in paternal age, but these findings were not statistically significant (de novo vs. sporadic ORs 30-34 = 1.7 [0.7-4], ≥ 35 = 1.3 [0.5-3.3]; de novo vs. familial ORs 30-34 = 2.8 [1.0-8.4], ≥ 35 = 1.6 [0.6-4.6]). Our study suggests a weak paternal age effect for Rb resulting from de novo germline mutations consistent with the paternal origin of most of these mutations.